Re: [PATCH] bnx2fc: do not add shared skbs to the fcoe_rx_list

[Maurizio Lombardi <mlombard@redhat.com>]

Hi Eddie,

On 08/23/2014 01:02 AM, Eddie Wai wrote:
> is this still a problem?  The mail reflector seems to work for me...
> 

Works for me now.

Regards,
Maurizio Lombardi

>>
>> On 07/25/2014 10:02 AM, Maurizio Lombardi wrote:
>>> In some cases, the fcoe_rx_list may contains multiple instances
>>> of the same skb (the so called "shared skbs").
>>>
>>> the bnx2fc_l2_rcv thread is a loop that extracts a skb from the list,
>>> modifies (and destroys) its content and the proceed to the next one.
>>> The problem is that if the skb is shared, the remaining instances will
>>> be corrupted.
>>>
>>> The solution is to use skb_share_check() before adding the skb to the
>>> fcoe_rx_list.
>>>
>>> [ 6286.808725] ------------[ cut here ]------------
>>> [ 6286.808729] WARNING: at include/scsi/fc_frame.h:173 bnx2fc_l2_rcv_thread+0x425/0x450 [bnx2fc]()
>>> [ 6286.808748] Modules linked in: bnx2x(-) mdio dm_service_time bnx2fc cnic uio fcoe libfcoe 8021q garp stp mrp libfc llc scsi_transport_fc scsi_tgt sg iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul crc32c_intel e1000e ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper ptp cryptd hpilo serio_raw hpwdt lpc_ich pps_core ipmi_si pcspkr mfd_core ipmi_msghandler shpchp pcc_cpufreq mperf nfsd auth_rpcgss nfs_acl lockd sunrpc dm_multipath xfs libcrc32c ata_generic pata_acpi sd_mod crc_t10dif crct10dif_common mgag200 syscopyarea sysfillrect sysimgblt i2c_algo_bit ata_piix drm_kms_helper ttm drm libata i2c_core hpsa dm_mirror dm_region_hash dm_log dm_mod [last unloaded: mdio]
>>> [ 6286.808750] CPU: 3 PID: 1304 Comm: bnx2fc_l2_threa Not tainted 3.10.0-121.el7.x86_64 #1
>>> [ 6286.808750] Hardware name: HP ProLiant DL120 G7, BIOS J01 07/01/2013
>>> [ 6286.808752]  0000000000000000 000000000b36e715 ffff8800deba1e00 ffffffff815ec0ba
>>> [ 6286.808753]  ffff8800deba1e38 ffffffff8105dee1 ffffffffa05618c0 ffff8801e4c81888
>>> [ 6286.808754]  ffffe8ffff663868 ffff8801f402b180 ffff8801f56bc000 ffff8800deba1e48
>>> [ 6286.808754] Call Trace:
>>> [ 6286.808759]  [<ffffffff815ec0ba>] dump_stack+0x19/0x1b
>>> [ 6286.808762]  [<ffffffff8105dee1>] warn_slowpath_common+0x61/0x80
>>> [ 6286.808763]  [<ffffffff8105e00a>] warn_slowpath_null+0x1a/0x20
>>> [ 6286.808765]  [<ffffffffa054f415>] bnx2fc_l2_rcv_thread+0x425/0x450 [bnx2fc]
>>> [ 6286.808767]  [<ffffffffa054eff0>] ? bnx2fc_disable+0x90/0x90 [bnx2fc]
>>> [ 6286.808769]  [<ffffffff81085aef>] kthread+0xcf/0xe0
>>> [ 6286.808770]  [<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
>>> [ 6286.808772]  [<ffffffff815fc76c>] ret_from_fork+0x7c/0xb0
>>> [ 6286.808773]  [<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
>>> [ 6286.808774] ---[ end trace c6cdb939184ccb4e ]---
>>>
>>> Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
>>> ---
>>>  drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 7 +++++++
>>>  1 file changed, 7 insertions(+)
>>>
>>> diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
>>> index 785d0d7..a190ab6 100644
>>> --- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
>>> +++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
>>> @@ -411,6 +411,7 @@ static int bnx2fc_rcv(struct sk_buff *skb, struct net_device *dev,
>>>  	struct fc_frame_header *fh;
>>>  	struct fcoe_rcv_info *fr;
>>>  	struct fcoe_percpu_s *bg;
>>> +	struct sk_buff *tmp_skb;
>>>  	unsigned short oxid;
>>>  
>>>  	interface = container_of(ptype, struct bnx2fc_interface,
>>> @@ -423,6 +424,12 @@ static int bnx2fc_rcv(struct sk_buff *skb, struct net_device *dev,
>>>  		goto err;
>>>  	}
>>>  
>>> +	tmp_skb = skb_share_check(skb, GFP_ATOMIC);
>>> +	if (!tmp_skb)
>>> +		goto err;
>>> +
>>> +	skb = tmp_skb;
>>> +
>>>  	if (unlikely(eth_hdr(skb)->h_proto != htons(ETH_P_FCOE))) {
>>>  		printk(KERN_ERR PFX "bnx2fc_rcv: Wrong FC type frame\n");
>>>  		goto err;
>>>
> Seems logical, but this patch requires some testing which ought to be
> verified by the Qlogic team.  Thanks.
> 
>